1. Field of the Invention
The present general inventive concept relates to a photosensitive body, and more particularly, to a photosensitive body having a grounding device to electrically connect a photosensitive drum and a shaft, and to an image forming apparatus having the above photosensitive body.
2. Description of the Related Art
An image forming apparatus, such as a printer, a copying machine or a fax machine, prints an image on a printing medium according to an input image signal. Of the various types of image forming apparatuses, an electrophotographic image forming apparatus includes a photosensitive body having a photosensitive layer made of a photoconductive material.
An electrophotographic image forming apparatus is configured such that a photosensitive body is charged to a predetermined electric potential, light is scanned to the charged photosensitive body to form an electrostatic latent image on a surface of the photosensitive body, and a toner is supplied to the electrostatic latent image to develop the electrostatic latent image into a visible image. The visible image formed on the photosensitive body is transferred onto paper supplied from a paper feeding device. Thereafter, a residual electric potential on the surface of the photosensitive body is removed to initialize the surface of the photosensitive body, and then a development process of the next cycle is carried out.
In order to obtain an image of good quality through the development process, the photosensitive body is needed to be grounded by being electrically connected to a main body of the image forming apparatus.
The photosensitive body generally includes a photosensitive drum provided with a photosensitive layer on an outer peripheral surface thereof, a flange coupled to an end portion of the photosensitive drum, a shaft electrically connected to the main body of the image forming apparatus and rotatably supporting the flange, and a grounding device to electrically connect the photosensitive drum and the shaft.
Korean Patent Registration No. 0574052 (Publication No. 1020050035548) discloses a grounding member which includes a plate-shaped body having a shaft hole, through which a shaft passes, a first grounding piece provided near the shaft hole and contacted with an outer surface of the shaft, and a second grounding piece extending from an outer periphery of the plate-shaped body and contacted with an inner surface of a photosensitive drum.
In the above-mentioned grounding member, when the shaft passes through the shaft hole, the first grounding piece is deformed by the shaft, and is elastically contacted with the outer surface of the shaft. Also, when the flange is coupled to the photosensitive drum, an end portion of the second grounding piece is bent by the photosensitive drum, and is elastically contacted with the inner peripheral surface of the photosensitive drum.
However, in the above grounding device, because the second grounding piece is contacted with the inner peripheral surface of the photosensitive drum only by an elastic force of the second grounding piece, the second grounding piece cannot be in secure contact with the photosensitive drum, and thus there is a limitation in stably maintaining an electric connection state. Especially, in a case where the photosensitive drum is made of aluminum, an oxide film is formed on the inner peripheral surface of the photosensitive drum. Thus, if the contacting force of the grounding device to the photosensitive drum is not large enough to destroy the oxide film, the grounding state cannot be stably maintained.
Also, the conventional grounding device has a problem such that when the photosensitive body rotates, the first grounding piece is worn out by friction with the shaft, which causes deterioration of a connection between the grounding device and the shaft.